Synopsis
Diagnose screen-detected and symptomatic ductal carcinoma in situ accurately, exclude occult invasion, tailor breast and axillary surgery, use radiotherapy and endocrine risk reduction appropriately and avoid metastatic overtreatment.
- DCIS consists of malignant epithelial cells confined within breast ducts by an intact myoepithelial layer and basement membrane; pure DCIS cannot metastasise.
- Most cases are detected as mammographic microcalcification rather than a palpable lump, but a mass or nipple discharge increases concern for more extensive disease or occult invasion.
- Stereotactic or tomosynthesis-guided vacuum-assisted sampling is preferred for many calcification-only lesions because it obtains representative tissue and confirms that target calcification was removed.
- Pathology should report nuclear grade, necrosis, size or extent where assessable, margins after surgery and ER when endocrine risk reduction is being considered.
- Do not request routine CT, bone scan or PET-CT for pure DCIS; systemic staging adds radiation and false positives without a metastatic mechanism.
- Breast-conserving surgery is appropriate when the radiological field can be excised with clear margins and an acceptable breast result; radiotherapy usually follows to reduce local recurrence.
- Mastectomy is appropriate for diffuse or multicentric extent, inability to achieve margins, an unfavourable lesion-to-breast ratio or informed preference and usually cures local disease without postoperative radiotherapy.
- Do not perform routine sentinel-node biopsy with breast-conserving surgery for pure DCIS. Offer it with mastectomy because lymphatic mapping cannot be performed reliably afterwards if invasion is discovered.
- Endocrine treatment after breast-conserving therapy for ER-positive DCIS can reduce ipsilateral and contralateral breast events but does not treat distant disease or replace surgery.
- Chemotherapy and HER2-directed therapy have no role in pure DCIS; if invasion is found, reclassify and treat the invasive component.
- Explain absolute recurrence reduction and competing treatment harms because a screen-detected non-invasive lesion can otherwise feel indistinguishable from metastatic-risk cancer.
- Continue mammographic surveillance after conservation and after unilateral mastectomy of the remaining breast, with prompt diagnostic assessment of new symptoms.
Key red flags
A palpable mass, architectural distortion, suspicious node or extensive high-grade calcification increases the probability that biopsy has under-sampled invasive cancer.
New bloody single-duct discharge, nipple retraction or Paget-like nipple change may represent extensive ductal disease or an occult invasive component.
Rapid postoperative swelling, severe pain, hypotension or high drain output suggests haemorrhage requiring immediate surgical review.
Fever, spreading erythema, purulent drainage or implant exposure after surgery requires urgent infection and source-control assessment.
Positive or very close margins after repeated excision require specialist review because residual field disease and further cosmetic harm may favour mastectomy.
Microinvasion or stromal invasion on excision changes nodal, receptor, systemic and sometimes margin decisions and requires prompt MDT restaging.
Investigation priorities
Characterise morphology and distribution of calcification and estimate the full field requiring biopsy and excision.
Sample calcification widely enough to diagnose grade and assess for invasive or atypical components.
Management branches
Screening or symptomatic mammography identifies suspicious calcification without proven invasion.
- Obtain diagnostic magnification views, map number and span of groups and add ultrasound when a mass, duct or node is present.
- Perform stereotactic or tomosynthesis-guided vacuum-assisted biopsy, confirm target calcification in the cores and place a marker for later localisation.
- Review radiological and pathological concordance at the breast MDT and repeat sampling when tissue does not adequately explain the imaging category.